Trash-heap Water Wheel Recharges IPhone In The Woods

We’ve all been there – hiking in the woods with a dead phone battery. No GPS, no way to Tweet that selfie from some hill with a great vista. It’s a disaster! But not if you have access to a little trailside junk and have the ingenuity to build this field-expedient water wheel generator to recharge your phone.

OK, it’s a stretch to imagine finding all the things needed for [Thomas Kim]’s hack. We’re only guessing at the BOM – the video below has little commentary, so what you see is what you get – but it looks like a garbage can at the trailhead might at least yield the materials needed to build the turbine. Water bottle bottoms and a couple of plastic picnic plates form the Pelton-like impeller, the frame looks like an old drying rack, and the axle appears to be a campfire skewer. But you might have a hard time finding the electrical side of the build, which consists of a stepper motor, a rectifier, and an electrolytic cap. Then again, you could get lucky and find a cast-off printer by the side of the road. No matter how he got the materials, it’s pretty cool to see an iPhone recharging next to a babbling brook in the woods.

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33 thoughts on “Trash-heap Water Wheel Recharges IPhone In The Woods”

As far as renewable energy goes, I’m surprised that water wheels don’t have more traction. I understand the disruption that building a dam can cause to wildlife, but a wheel seems like a decent compromise of envrio impact and generating pretty reliable power. Are there drawbacks/issues I’m missing?

There has to be a difference in the elevation of water called “Head”. The greater the head the greater the potential energy than can be harvested. The only natural place to find this is a water fall. Other wise you have to cut into the land. So the land cost is tremendous if it doesn’t naturally exist.

The other alternative is to build a dam to create the head. Which has an even greater impact.

I know an instance of domestic hydropower that runs around 250 watts that used over a hundred feet of pvc penstock to the Pelton wheel. The stream across the property was relatively small and the relief wasn’t that great. The generator kept a charge on a bank of flooded cell lead-acid batteries.

There were complications: in the winter the penstock could freeze and burst if it wasn’t emptied before it got too cold. The water that was taken from and then returned to the stream was a relatively small proportion of its flow, so it was about as low impact as possible.

Diverting the flow of water is a third option but this can have even more ecological consequences (legal ones too; always check your deed first).

In any case Im not arguing against small use cases; I’m explaining why we don’t see more of it. Water wheels wouldn’t exist if they weren’t useful. My point was that if you want to take more than what nature has provided you there you will either pay a huge construction or ecological cost.

“250 watts” is the issue there. For all the millions of people who don’t live near streams, you need hundreds of megawatts and gigawatts. There just isn’t enough naturally-occurring water to provide most of that.

Normal hydroelectric power generation requires a dam (potential energy). The other type (kinetic energy) relies on speed of the water: it is enough to just immerse your propeller/turbine into the water. This second type requires relatively fast moving water though.

Generally speaking that second type is a whirling razor blade of death for stream life, so there’s a nutrient rich plume below it composed of freshly pureed insects and other aquatic lifeforms, which in turn distorts predator/prey relationships in the same way that the 100 years war encouraged man-eating wolves in Europe.

You can use wedgewire grating and sacrifice some flow to ameliorate this problem, but most hydro installations just ignore it.

And of course if you dam the river you block economically important fish and eel migrations, unless you accommodate them with fish ladders and so forth.

Hydro _can_ be done withotu wrecking the environment, but it usually isn’t.

This one is pretty simple. Google “Stepper Motor Generator” to find some circuit examples. They’ll consist of a bridge rectifier and a smoothing capacitor as a bare minimum. This could be a fun beginners project as long as you don’t plug anything sensitive into the unregulated voltage output.

i live in the woods already and have done for 20 years. if it were me i would use a phone that draws less power for a start. then i would use a solar panel, then if i had all the bits he has i would build a banki turbine instead. grumpy old fart that i am.otherwise it is a nice build just could be a better build. plus with solar you are not dependent on a stream.

A phone that “draws less power” normally has also less functions, so I would NOT use like to use it, although I would never buy Apple stuff. Especially when I am traveling my phone also has to function as computer and GPS. So it uses more power than in everyday life (when I am sitting most of the time in front of a PC) and it could not be substituted with a dumbphone. So the necessary power has to be provided – a laptop would need even more power.

but electrical power normally is more useful than hydrogen. Except with expensive fuel cells, hydrogen can only be burned for heat, but for heat you can just burn ordinary wood, without wasting precious electricity.

I don’t know, but I would guess that this is illegal in many places (like the US); you know, environmental impact, generating power without a licence, etc. After all, until just a few weeks ago it was completely illegal in Colorado to collect any amount of rainwater. Even from your own property. Even from what fell on your own head.

Those sound more like state laws to me. No doubt that stuff is limited to western states where water is more limited and especially ones where water thirsty cattle ranchers have big roles in government.

Why do westerers so often try to present their own local laws as representing our whole nation? The only concern about this out east would be that he pick up his toys when he is done rather than leave them to return to their previous existance as trash, this time in the middle of a creek.